What is the diff ratio for the XP Falcon?
There isn’t a single diff ratio for the XP Falcon. Factory rear-end gear ratios for XP Falcons ranged roughly from 2.75:1 to 3.50:1, with 3.00:1 being common on many standard six-cylinders and 3.25:1 or 3.50:1 options appearing on certain V8 or performance variants. The exact ratio depends on the model, engine, transmission, and production date, so checking the car’s build data is essential.
Context: the XP Falcon and its axle options
The XP Falcon lineup, produced by Ford Australia in the mid-1960s, included a variety of body styles and engine choices. This breadth meant multiple differential options were available from the factory. Understanding the diff ratio is important for performance, odometer accuracy, and restoration accuracy.
Typical factory ratios by variant
Here are the ratios Ford Australia offered across the XP Falcon range. Availability varied by engine, transmission, and production period.
- 2.75:1 — offered on some lighter configurations or special-order setups; favored highway cruising in specific builds.
- 3.00:1 — the most common ratio for many standard six-cylinder XP Falcons with manual gearboxes.
- 3.25:1 — a balanced option often chosen for V8 or higher-torque variants to blend launch feel with cruising comfort.
- 3.50:1 — used on certain GT or V8 configurations and other performance-focused setups where stronger low-end torque was prioritized.
In short, these options cover the typical spectrum Ford Australia provided for the XP Falcon. The exact ratio for a given car depends on its original specification and production date.
How to verify the diff ratio on an XP Falcon
To determine the precise diff ratio of a specific XP Falcon, consult the axle data and build documentation, which were issued with the vehicle when new.
- Inspect the axle data plate or tag for a ratio code; cross-reference the code with Ford Australia catalogues or restoration databases to translate it into a numeric ratio.
- Check the differential housing for stamping codes and decode them using period Ford service literature or a qualified classic-car specialist.
- Review the original build sheet, window sticker, or dealer option sheets if available, as they often list the specific axle ratio installed at factory.
After you identify the ratio, ensure related driveline components (speedometer gear, driveshaft length, and tire size) are calibrated accordingly for accurate performance and readings.
Impact on performance and driving characteristics
The diff ratio influences acceleration, engine RPM at highway speeds, and fuel economy. A lower numerical ratio (for example, 2.75:1) typically lowers highway RPM and can improve fuel economy, but may slightly reduce off-the-line torque. A higher numerical ratio (such as 3.50:1) enhances launch and mid-range torque but raises engine RPM at cruising speeds, which can affect fuel consumption and noise levels during highway driving.
Summary
The XP Falcon’s diff ratio is model-specific rather than universal. Configurations ranged from about 2.75:1 to 3.50:1, with common setups around 3.00:1 for many six-cylinders and 3.25:1 or 3.50:1 for V8 or performance variants. To know the exact ratio for a particular car, verify the axle code, build sheet, or Ford Australia documentation, and adjust any dependent systems accordingly.
In summary: check the original documentation or axle codes to confirm your XP Falcon’s precise differential ratio, as it varies across the lineup and production period.
What is an XP Falcon worth today?
Briarcliff767 : In the current market, classic cars of this type range from $24,000 to $32,000 if they are in excellent condition, meaning no imperfections in the paint, original paint, no rust, and with low mileage. If it has had one owner, you can expect a higher value.
How many XP Falcons were made?
Production of the XP Falcon range totaled 70,998 vehicles prior to its replacement by the XR Falcon in September 1966.
What is the diff ratio for XG Falcon?
XG diff ratio should be 3.27:1, centre should be open 4 pinion 28 spline (not LSD).
What cars have a M86 diff?
Vehicle Applications:
- Holden Commodore selected VY-VZ One tonne Ute & Crewman.
- Ford Falcon, BA, BF & FG XR6T and XR8 models including FPV variants.
